Tunnel-boat.



0Q H. FOWLER.

Patented Aim 16, 1918.

2 SHEETS-SHEET 1.

INVENTOR 'ATTORIVEV c. HQ FOWLER.

TUNNEL BOAT. APPLICATION FILED JAN-15.1916.

. IIVI/EIVTOR I M1734 2 SHEETS-SHEET 2.

Patented Apr. 16,1918.

A r'romvm 2 I it FEQQ CARL H. FOWLER, or NEW roan, iv. Y.

TUNNEL-BOAT.

Application filed. January 15, 1916. Serial No. 72,201,

To all whom it may concern:

Be it known that 1 CARL H. FOWLER, a citizen of the United States,residing in the city, county, and State of New York, have inventedcertain new and useful Improvements in Tunnel-Boats, of which thefollowing is a specification.

My invention relates especially to boats of light draft, adapted tonavigate through shallow water, which boats are provided 7 with tunnelsor chambers within the body of the b=oat,'in which screw-propellers aresituated. Boats of this character are described in my Patent N 0.1,132,923, granted March 23, 1915, for improvements in shallow waterboats. As is there described, the tunnel or tunnels have a vacuum pumpconnected therewith, and preferably a vacuum chamber superimposed abovethe tunnel or tunnels in which water is raised to a desired level by theoperation of the vacuum pump, the bottoms of the tunnels being openinthe bottom of the boat, so that thetunnels and vacuum chamber above thesame are constantly, during operation, filled with water in which thepropellers are entirely submerged, the water usually extending for anumber of feet above the propeller in a vacuum chamber. Thisconstruction makes practicable the operation of the propeller in waterof density equal to that it wouldhave if situated the same number offeet beneath the bottom of an ordinary boat.

My present invention relates to improvements in the type of boatreferred to, which make for greater efliciency and economy ofconstruction, operation and space. A part of my invention consists inoperating a relatively small propeller in a tunnel of correspondinglysmall cross-section at high speed by suitably connecting the propellershaft by gears or preferably by a chain drive, to an engine ofrelatively slow speed. Tunnel boats of the old type heretofore havebeen, so far as I am aware, direct-connected to the prime mover, andhave been found tov have a limited range of usefulness. In my improvedconstruction I drive the propeller at in increased speed (as for exampletwice as many revolutions per minute as the shaft of the engine fromwhich power is taken) and thus reduce the necessary diameter and size ofthe propeller, so that its effective equal to that of a larger propellerrotated more slowly by direct connectionwith the engine. This procedureis rendered more efficient by the use of a vacuum chamber above thetunnel, as stated, whereby a firm body of water is provided at the pointat which the propeller operates. It is a matter of common knowledge thata small propeller at high speed in the ordinary boat in shallow water isalmost useless for it produces cavitation to such an extent that itchurns up an exceedingly foamy medium of poor resisting power in whichto operate. For this reason a high speed propeller in shallow water hasheretofore never been practicable or efficient. My present inventionovercomes these difficulties.

Another feature of my invention consists in the use of a plurality ofcomparatively small tunnels, distributed through the length of the boat,some in the fore part,some in the center, and some in the afterpart'of acomparatively long boat. may be situated in longitudinal alinement or inone or moreseries of tunnels, each series comprising tunnels inlongitudinal alinement, and each tunnel or group of tunnels containing apropeller or propellers operated from a separate engine, or by chaindrive from one central shafting. Thus a boat may be provided with, forexample, two, three or more tunnels in one line or on each side, thepropellers in the forward pair of tunnels being 7 driven preferably by aspeed-increasing chain or gear drive from an engine of comparativelyslow speed. The next or second pair of propellers can be similarlyoperated by a separate engine, and the third or rear pair of propellersoperated by a third engine. Under this arrangement allowance can be madefor the backward speed of the water as thrust from the first propellersand partly received into the tunnels of the second and succeedingpropellers. This canbe compensated either by increasing the propellerspeed of the second propellers by means of the sprockets and chains orby direct engine control of the second engine, or also by increasing thepitch of the second and each successive propeller blades themselves.

The arrangement herein described makes possible the use of shortshafting only and the distribution of the propelling power in smallunits throughout the length of the boat, and does not concentrate thestrain of propulsion at the extreme stern, or at one point, as do mostboats. On the contrary,

These tunnels oration.

V hull construction can A number of advantages arise from theconstruction described By using the chain drive with difierent sprocketsa wide variation of propeller speed can be obtained without changing theengine speed, thus making possible the finest adjustments especiallywhen a series of tunnels are installed. .The use of the chain drivemakes it practicable to place the engine with. its power shaft eitherabove or below or to the side of the propeller shaft, and also does awaywith the necessity for absolutely perfect and rigid alinement. Byincreasing the propeller speed and reducing the diameter ofthe'propeller and tunnel from that which would otherwise be necessary,the dead weight of the water carried by the tunnel is very considerablydecreased since the weight of the water in the tunnel variesapproximately as the cube of the diameter of the propeller. Also, thespace occupied in the boat by the tunnel or tunnels is correspondinglydecreased, leaving more room in the hull available for carrying freightor passengers. High speed engines are much more expensive and lessdurable than slower engines. The life of an engine is much greater whenit is operated at mod erate speeds than at high speeds. In my deviceless expensive engines of low or moderate speeds may be successfullyused, while at the same time the propeller is rotated efficiently atmuch higher speed. Owing to the distribution and division of the powerunits of propulsion throughout the length of the boat, a lighter andless expensive form of be used than would otherwise be practicable.

In order that. a clearer understanding of my invention may be had,attention is hereby directed tov the accompanying drawings forming partof this application and illustrating certain embodiments of myinvention. In the drawings, Figure 1 represents a plan view of the boatequipped with one form of my invention, Fig. 2 is a vertical section ofthe. same taken on line 2-2 of Fig. 1, Figs. 3 and 4: are cross-sectionstaken. on lines 33 and l4 respectively of Fig. 2, Fig. 5 is a plan viewof a boat having a pair of tunnels, one at each side of the boat, Fig. 6is a plan view of a boathaving a plurality of tunnels in pairs, inconnection with a pluropeller chamber :2 which preferably has a orwardwall 3 sloping upwardly with a gradual curve from the keel line andrearwardly, and a rear upper wall 4 sloping rearwardly and downwardly.The tunnel 2 terminates in the stern of the boat at a point. below theminimum water line and preferably above the keel line of the boat. Thecross-section of the tunnel is preferably as shown in Fig. 3. Thestand-pipe or vacuum chamber 5 is mounted above and connects with thehighest point of chamber 2, vacuum chamber 5' communicating by a passage6 with a vacuum pump (not shown), whereby the tunnel 2 and vacuumchamber 5 may be filled, to as great an extent as is desired, with waterdrawn through the bottom of chamber 2.

The propeller shaft '7 extends through a suitable bearing 8 into thetunnel or propeller chamber 2 and is provided therein with the propeller9. The opposite or forward end of shaft 7 is provided with a bearing 10,which preferably comprises a thrust bearing, to take the forward thrustof the shaft when the propeller is advancing. Bearing 8 should beprovided with means for taking the rearward thrust of the propellershaft when the propeller is reversed. In the preferred construction boththe shaft 7 and the upper rear wall l of the tunnel slope downwardlytoward the rear at the same slight inclination.

The engine 11, which may be any suitable prime mover, such as aninternal combustion engine, has a shaft 12 supported in a bearing 18.Shafts 12 and 7 are provided with sprocket-wheel's 14 and 15 over whichsprocket chain 16 operates, sprocket it being of a considerably largerdiameter, such for example as twice the diameter of sprocket 15, so thatshaft 7 and propeller 9 rotate at a considerably higher rate than ongine shaft 12. Gear connections may, of course, be used instead of thesprocket chain drive, but the latter are considered preferable.

It is, of course, understood that the drive described rotates propeller9 at a rate of considerable velocity, and that propeller 9 isaccordingly of a much smaller diameter than would otherwise bepracticable for driv-- ing the boat at the same speed. It should benoted that while I speak of the propeller as being situated withintunnel 2, this should not be taken as meaning that the propeller isnecessarily situated entirely within the lines of the hull, since thesame may ex tend somewhat beneath the keel line of the boat when it isnot essential that the draft of the boat be at a minimum. It is,however, essential that means, such as the stand pipe 5 and theconnection from the same to p a vacuum pump, be provided to cause thepropeller to rotate in water having a density and firmness equivalent tothat which would be encountered, if the propeller were located at aconsiderable distance beneath the surface of the water navigated. Itshould also be understood that the tunnel extends no farther upwardlywithin the boat than is necessary to accommodate the propeller, so thatusually the highest point of the propeller chamber proper situated abovethe propeller is in substantially the same hori 'zontal plane as theupper edge of the propeller wheel. As has been explained above, theweight of dead water carried in tunnel 2 is greatly decreased by thusdecreasing the diameter of the propeller wheel and dimensions of thetunnel, with a consequent economy of power.

A low limit is ordinarily found for the efiicient operation of screwpropellers in shallow waters. This is because of the fact that atgreater speeds the propeller cavitates, power is wasted and allefiiciency lost. With my construction this result is overcome by thesolid water being given to the" propeller at all times by use ofatmospheric pressure, because of the suction exerted in the vacuumchamber by the vacuum pump, so that the propeller can effectively beoperated at a considerable speed.

In Fig. 5 the boat 1 is shown as provided with a pair of tunnels 2, 2,each of which may be imilar in construction to the tunnel shown in Fig.2. These'tunnels are located One at each side of the boat and areprovided with superimposed vacuum cham bers 5, 5, as shown in Fig. 8,these vacuum chambers being connected with a vacuum pump as describedabove. The propellers 9, 9 are mounted within tunnels 2, 2 on shafts 7',7 which extend into the interior of the boat in the same manner as shaft7 in the form of my device already described. The shaft 12 of engine 11is provided with a pair of similar sprocket-wheels 14, 14, sprocket 14being connected by sprocket chain 16 with a smaller sprocket 15 on oneshaft 7 and sprocket 14 being connected by chain 16 with a sprocket 15,similar to sprocket 15, on the other shaft 7 By this means propellers 99 are rotated at a speed considerably higher than that of the engineshaft and the diameters of the propellers and cross-sections of thetunnels are correspondingly reduced.

In a pleasure boat the tops of the tunnels may be utilized as supportsfor seats and lockers. In a freight carrying boat, such as a canal boat,on which all or a. greater part of the load is carried as a deck loadand not be located in the otherwise Waste'space under the deck.

In Figs. 6, 7, 8 and 9, a construction is shown in which a series oftunnels 1 2, 3, etc., are placed in longitudinal alinement adjacent oneside of the boat and a second series of similar tunnels 1 2 3 etc., areplaced in longitudinal alinement adjacent the other side of the boat,the forward tunnels 1 and: 1 being alined transversely of the boat andthe other pairs of tunnels of the two series being similarly arranged.In this instance the rear pair of tunnels are similar to the tunnelshown in F ig. 2, with the rear orifices thereof preferably extendingthrough the stern of the boat at a point between the minimum water lineand the keel line. The rear walls of the other tunnels extend downwardlyto the keel line of the boat, the cross-sections of all the tunnelsbeing the same as shown in Fig. 8.- Each tunnel is provided with avacuum chamber 5, or if desired a common vacuum chamber may be providedfor each transverse pair of tunnels suitably connected. A single vacuumpump may be provided for the whole system with suitable connections tothe differ- 'ent vacuum chambers, or a separate pump may be provided foreach transverse pair of tunnels. An engine 11" is provided for theforward pair of tunnels, the engine shaft 12 being suitably connected,as by sprocket chains 16 and 16 in the manner already described, to theshafts 7 7 of the propellers located within the forward pair of tunnels.Other engines, such as 11 and 11 are similarly connected to thepropeller shafts belonging to the other transverse pairs of tunnels.With this arrangement it is obvious that a considerable amount" of powermay be utilized while keeping the sizes of the engines and the crosssectional areas of the tunnels very low. This arrangement is especiallyvaluable for'use on a long non-rigid barge or boats such as are used invarious rivers. It is in brief applying to boat construction in apractical way the division of its power propulsion into a large numberof small units throughout the length similar in principle to thecentipede with its series of propeller power units.

It should be understood that my invention is not limited strictly to theexact details of construction described, but is as broad as is indicatedby'the accompanying claims.

Havlng now particularly described my invention, what I claim and desireto protect by Letters Patent is as follows 1. A boat having a series oftunnel chambers open at the bottom and longitudinally arranged, shaftsextending into said chambers from the interior of the boat, propellers &

thereon within said chambers, power-generating means, and connectionsbetween the same and said propeller shafts.

2. A boat, having a series of tunnel chambers-open at the bottom andlongitudinally arranged, shafts extending into said chambers from theinterior of said boat, propellers thereon Within said chambers, aplurality of engines and speed changing connections for driving saidpropeller shafts at speeds greater than the speeds of said engines.

3. A boat, having a longitudinal series of chambers therein, open at thebottom of the boat, with vacuum chambers above and connectedtherewith,shafts extending into said cltambers from the interior of the boat,propellers thereon, Within said chambers, vacminn-creating means forraising the Water within said propeller and vacuum chambers, a pluralityof engines and speed changing connections for driving said propellershafts at difierent speeds from the speeds of said engines.

a. A boat having a plurality of series of longitudinal propellerchambers, open through the bottom of the boat, shafts extending intosaid propeller chambers from chambers appertaining thereto, for drivingsaid propeller shafts at speeds greater than those of the engines.

5. A boat, having a plurality of series of longitudinal propellerchambers, open through the bottom of the boat, With vac uum chambersabove and connected With said propeller chambers, With vacuum creatingmeans for exhausting the air from said vacuum chambers, shafts extendinginto said propeller chambersfrom the interior of the boat, propellers onsaid shafts Within said chambers, a plurality of engines, speedincreasing connections between said engines and the propeller shafts ofthe propeller chambers adjacent thereto.

This specification signed and witnessed this 11th day of January, I

H. FOWLER.

CARL

lVitnesses:

J. H. WEBER, H. R. BROWN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

